1. Field of the Invention
The present invention relates to a method of producing an acid halide and the acid halide.
2. Description of the Related Art
The acid halide has been actively used as a synthetic intermediate for functional compounds such as pharmaceutical products and agricultural chemicals, or dyes. Especially, an acid halide having a bulky group enables a particular portion of the functional compound to be bulky. Due to that, it is expected to impart functionalities, for example, realization of a sharp color hue due to prevention of molecular rotation, and enhancement of chemical resistance, weather resistance, or the like due to protection of a fragile portion of the functional compound. Accordingly, the acid halide compound having a bulky group is useful. Further, in an acid halide having both a leaving group and a bulky group, a functional group such as an alkali-soluble group or a polymerizable group can be introduced thereto by replacement of the leaving group, thereby enabling to impart thereto further functionalities. Accordingly, the acid halide compound having both a leaving group and a bulky group is very useful.
As a method of producing an acid halide having a bulky group, there is a method of hydrolyzing an ester compound having a bulky group under alkali conditions, and then bringing the obtained carboxylic acid into reaction with thionyl chloride (for example, refer to J. Am. Chem. Soc. 1984, 106, 1010). However, in the case of producing an acid halide having a leaving group in accordance with the above method, there is a problem that a leaving group is eliminated at the time of producing a carboxylic acid, which results in a yield loss of an objective substance. Especially, the ester compound having a bulky group exhibits such rapid rate of hydrolysis that an elimination reaction progresses conspicuously. Accordingly, it is very difficult to synthesize the acid halide having both a leaving group and a bulky group. In order to suppress elimination of the leaving group, it is considered effective to produce the carboxylic acid having a bulky group under moderate conditions. As for the production methods of carboxylic acid having a bulky group, there are reported a method of reacting acid amide with sodium nitrite (refer to J. Am. Chem. Soc. 1957, 79, 2530), a method of oxidizing a ketone with nitric acid (refer to Journal of the Chemical Society, Perkin Transactions 2: physical Organic Chemistry, 1974, 1525), and a method of reacting a Grignard reagent with carbon dioxide (refer to Journal of the Chemical Society, Perkin Transactions 2: physical Organic Chemistry, 1974, 1525). However, even in these reactions, there are problems that the leaving group also reacts, which results in a yield loss of a target, and further, the reaction is hazardous and resultantly the reaction is not adequate to a mass scale production.
As a synthetic example of the carboxylic acid having a leaving group, a method of hydrolyzing an ester with trimethylsilyl iodide is reported (for example, refer to U.S. Pat. No. 6,204,278). However, there is a problem that trimethylsilyl iodide is expensive and in the case of producing a carboxylic acid having a bulky group, a long time is required for a reaction, which results in high production cost.
Further, in U.S. Pat. No. 6,204,278, synthesis of carboxylic acid chlorides in which a leaving group is a chlorine atom is described. However, any of the described carboxylic acid chlorides has no substituent or has a substituent as small as a methyl group. Accordingly, there is not known a synthetic method of an acid halide having both a leaving group and a bulky group.